The major emphasis of this project is on reaction kinetics in chemistry, particularly in low dimensional systems. Some work has also been done on models for diffusive transport in a disordered medium. Continuing some earlier work, PSL, together with a number of collaborators has done extensive work on characterizing intermolecular distances in reactions occurring in low dimensions. It has been shown that in a one dimensional system of the form A+B-B, with a single diffusing B molecule in the presence of many diffusing A molecules, the distance from the B to the nearest unreacted A molecule is proportional to a power of the time that varies between 1/4 and 1/2. A theory has been developed for diffusion in the presence of a molecule with a non-Markovian boundary. An international conference on non-classical chemical kinetics has been organized by the PSL, and will be held at NIH in March 1991.